Improved method of manufacturing- welded wkought-metal tubing



s. P. M. TASKER. METHOD OF MANUFACTURING WELDED WROUGHT METAL TUBING.

Patented June 22, 1869.

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Letters Patent No. 91,7 91, dated June 22,-18 we mPROVI-JD METHOD OF MANUFACTURING WEI-DEB WROUGHT-METAL TUBING.

The Sheduls referred. to in these Letters Patent and part of the'sa m e.

Be it known that I, STEPHEN P. M. TASKER, of Philadelphia, in the county of Philadelphia, and State of Pennsylvania, have invented a new and improved Method oiManuf'acturingWrought-Metal Tubing; and I do hereby declare the following is a full and exact description thereof, reference being had to the accompanying drawings, making part of this specification. in which- Figure 1 is a front elevation,

Figure 2 is a side elevation, and

Figure 3, atop view of one form of machine adapted to my method of making tubes.

The letters oi'rference upon all the drawings relate to corresponding parts.

To enable others skilled in the art; to have a full comprehension of my invention, I will proceed to describe the construct-ion and operation of the particular form of machine shown in the drawings, where- A A is a frame, or stand;

B B are pedestals, or bearings;

C O are spur-gear wheels;

D D are mitre-gear wheels;

E E or F l are, either one or the other of them, as

most convenient for the application of power, main driving or transmitting-shafts;

G G are roll-shafts; H Hare rolls; and

I I is the mandrel, which mandrel is supported, at,

one end, by a stand, not shown on the drawings.

The pedestals, or hearings of the several shafts are pro ided with adjustments, not shown on the drawings, by means of screws, wedges, or other devices well known to mechanics; and the shafts have collars, or

steps, whereby the rolls can be set, in the performance ofthe work. As these means of adjustment present nothing of i'iovelty, and are readily understood. no further description of them is deemed essential at this place.

The outer end' of the mandrel I I, which is carried by the stand, (not shown on drawings,) is so far distant from the rolls H H asto'allow the finished tube to pass over thexmandrel, while the inner end of the mandrel, which shapes, or forms the inside of thertnbe, is placed in the openings made by the grooves of the rolls. Where the mandrel lays in the grooves, there is a slight enlargement of the b0dy,at K K, so that, in the process of making, the tube fits loosely on the rest of the mandrel after the grooves are passed.

The end of the mandrel is also separate from the stem, at L L, so thatit can be drawn from the tube after its completion, by the removal of the end K K.

This construction of mandrel is the one usualiy adopted in rolling tubes with a mandrel, as applied-to tubes made with a lap-weld.

In making tubes with a but-weld, except where it is desirable to thin the metal of the tube, no mandrel whatever is required or used. i i

The mode of operation of the machinery shown on the drawings, consists merely in giving a rotary motion, in one or. the other direction,- to the driving-shaft Eor F. It will be noticed that thisarran'gement places two pairs of rolls, one pa'irin advance of the other, with their axes in planes. at right angles, so that the bite upon the metal between the first pair of rolls and-the mandrel, or the compression of the tube, if no mandrel is used, is qnartering with the bite, or compression which the second pair of rolls will produce.

To give a full understanding of the nature of my invention, I will state, as 'briell y as possible, the action of rolls upon the tube, or skelp which forms the tube,

where two or more rolls which converge about the tube, having their axes in the same plane, 'are used, with or without a mandrel in the combination, being the commonly-practised method of manufacturing tubes, both in this country and in England. In this explanation I will again refer to the drawings, in which- Figure 4 shows a section of the nnbent sheet of mctahtechnically known as a skelp, from which a tube is made;

Figure 5' shows a section of the bent skelp, as prepared for welding in therolls; and

Figure 6 shows a section of the unfinished tube, when rolled by two rolls.

The skel p has parallel edges, which have been scarfed, or bevelled away the entire length, when lap-welded tubes are to be made, but has square, sound edges when but welded tubes are to be made. It is bent up, from the form shown in fig. 4, into that shown by fig. 5, as a preliminary operation to the welding in the rolls, at a heat much below a. welding-heat. It is then permitted to 006i and cast ed the scale, or film of ox idea which has been formed by exposure of the metal, at the bending-heat, to the air.

To weld on the bendingheat, or bend on the welding-heat, has been found impracticable, although such schemes have. been proposed and patented. The surfaces to be welded must be broughtin contiguity free from scale.

Contact with the air, or with cold iron, will reduce the temperature of the metal below that at which the scale will fuse away, and the weld be nnsound, if not entirely defective. It is even impossible to save the heat of bending by replacing the skelp when bent in the welding-furnace, as the scale formed by exposure to the'air then melts oh, and, forming a. 'fiu'x for the bottom of the furnace, not only destroys the furnace, but gathers as a glass on the sides of the skelp, :form-' ing lumps, whichmake indentations on the tube when passing the rolls.

The form shown in fig. 5 is that ofa loose scroll,

with the edges overlapping each other a. little more than thewidth of the bevelling, or, generally, about three times the thickness of the metal, so that there is a double thickness of metal at the unwelded joint,

(with thinned edges',) to be compressed, ,when at a weld.-

opened out, to allow the iron to spread, while the corners of the g'roovesare rounded, so that they shall not mark or cut the tube while it passes through the "rolls and over the mandrel.

The entire space between the rolls and the mandrel is justas much less thana section of the skelp, when bent, as'itis found 'practicably possible for the draught of the rolls to pull the skelp over the mandrel without sticking. It follows that a section .of a tube, after its first'or welding-heat, is that shown on fig. 6, and can be compared to that of a Roman capital letter O, (sup posing the hole to be circular,) with two ribs, or fins,

't'ormed paitlyby the'corners ot' the grooves in the rolls,

and partly by a thin sheet squeezing out on -the faces j of the rolls.

j Great-care is needed to enter the lap of the skelp into the rolls so that the bite shall come upon it, and it is very desirable that the skelp should not twist, as

in this case a portion of the lap will come in the part- ..ing of the rolls, when a sound'weld is by no means so well insured.

This imperfect tube is then permitted to cool, and cast off v its scale, for the same reason that the bent skelpis cooled, andis then reheated, and again passed through the rolls',takiug care to enter the thick sides,

so that the work will now come on them. The' fins are either burned or fused away in the furnace, or are so softened as to roll down and weld tothe body of the tnbe,.and the tube will be of uniform thickness. In

this second rolling, not so much work is put upon the iron between the, mandrel and the rolls, consequently little or no fin is formed. The same difilculty of turning down is here 'encountered, and frequently a third or-fourth-rolling is needed to get a sound or a uniformly-thick tnbe.- It is possible to make and finish tubes at one-rolling, the inequality of thickness re .,ferred 'to is not regarded, and if the fins be chipped,

milled, or pared away.

With inferiorfliron, (the lower grades of iron being softer when hot,) the grooves in the rolls can be made -more nearly concentric than I have described, and the fin only is very objectionable.

With three or four rolls converging together, having their'axes'in the same planes, the forms of the grooves can be made altogethercobcentric to the mandrel, but

the fins produced by the partings are not only more in.

In rolling but-welded tubes without a mandrel, the

action of the rolls uponthe tube is very nearly as wit-h a mandrel, except that some portion of the effect is expended in making the hole orbore of the tube slightly oval. In but-weld tubes the thickness of metal relative to the diameter is necessarily so great that it acts as a mandrel to a considerable extent.

The improved method of welding, sizing, and smoothing wrought-metal tnbes';whi ch I have invent-ed, offers the means whereby, if anyfin orvinequality of thickness has been formed in the first. pair of rolls, it is rolled down and obliterated by the second pair; or if the skelp has twisted, so that the lap has not been brought under the biteof the first pair of rolls, such portion is immediatelyacted upon by the second pair of rolls, and the weld, the thickness, and the uniformity of the tube is thus insured.

I am aware that four converging rolls, ormore than two rolls, withtheir axes in the same plane, have been proposed and used in welding and sizing tubes. I am' aware that two pairs, or a series of pairs of rolls, in advance ,of ,each other, with the axes of each pair in planes at right angles, have been proposed for bending up metal forms, and in. one or more instances the combination of bendingw ith welding-tubes, by similar se: riesof rolls, has been proposed. 1- am aware thata pair of rolls, combined with a pair of milling cutters, rotat ing at right angles to the rolls, to remove the fin, has

been'proposed. I. am aware that two pairs of rolls, with the axes of each'pair in planes at" right angles,

'onepair'in advance of the other, have been proposed and used, under the name of universal mills for rolling sheet, band, or girder-iron. I am aware that series of pairs of rolls, in advance of each other, with axesof .the following pairs at right angles, have been proposed and used in rolling rods and bars.

of these machines nor the application of them to the I do not claim any various processes mentioned; but

What I claim as my invention, and desire to secure" by Letters Patent, isv The method of man ufacturing wrought-metal welded tubing from skelps previously prepared by bending, as hereinbefore described.-

' STEPHEN P. M. TASKER.

Witnesses:

J AMES Nrononson, Rom. Bmecs. 

